# HG changeset patch
# User Michael Pavone <pavone@retrodev.com>
# Date 1447818959 28800
# Node ID 90d54ccf95574cf208de2b00a5423367108aede8
# Parent  12b1a8a323066b3fc3825c37853f1925cd6bff37
Fix a bad interaction between the implementation of STOP and the way interrupt cycles are calculated. Prevent addition of refresh delays while VDP has the bus.

diff -r 12b1a8a32306 -r 90d54ccf9557 blastem.c
--- a/blastem.c	Mon Nov 16 22:00:32 2015 -0800
+++ b/blastem.c	Tue Nov 17 19:55:59 2015 -0800
@@ -175,6 +175,10 @@
 	context->target_cycle = context->int_cycle < context->sync_cycle ? context->int_cycle : context->sync_cycle;
 	if (context->should_return) {
 		context->target_cycle = context->current_cycle;
+	} else if (context->target_cycle < context->current_cycle) {
+		//Changes to SR can result in an interrupt cycle that's in the past
+		//This can cause issues with the implementation of STOP though
+		context->target_cycle = context->current_cycle;
 	}
 	/*printf("Cyc: %d, Trgt: %d, Int Cyc: %d, Int: %d, Mask: %X, V: %d, H: %d, HICount: %d, HReg: %d, Line: %d\n",
 		context->current_cycle, context->target_cycle, context->int_cycle, context->int_num, (context->status & 0x7),
@@ -241,9 +245,11 @@
 	vdp_context * v_context = gen->vdp;
 	z80_context * z_context = gen->z80;
 	//lame estimation of refresh cycle delay
-	refresh_counter += context->current_cycle - last_sync_cycle;
-	context->current_cycle += REFRESH_DELAY * MCLKS_PER_68K * (refresh_counter / (MCLKS_PER_68K * REFRESH_INTERVAL));
-	refresh_counter = refresh_counter % (MCLKS_PER_68K * REFRESH_INTERVAL);
+	if (!gen->bus_busy) {
+		refresh_counter += context->current_cycle - last_sync_cycle;
+		context->current_cycle += REFRESH_DELAY * MCLKS_PER_68K * (refresh_counter / (MCLKS_PER_68K * REFRESH_INTERVAL));
+		refresh_counter = refresh_counter % (MCLKS_PER_68K * REFRESH_INTERVAL);
+	}
 
 	uint32_t mclks = context->current_cycle;
 	sync_z80(z_context, mclks);